Various computer input devices are currently employed to provide a variety of input signals to computers for certain applications. For example, keyboards are an ideal method of inputting alphanumeric characters to the computer for most applications. Joysticks, often used with computer games, provide two-dimensional position signals based on wrist movement. Joysticks provide a particularly intuitive way of providing position signals that correspond to movement either within the plane of the computer screen, or movement perpendicular to the plane of the computer screen (i.e., virtual movement into and out of the screen). Joysticks, however, are bulky and at times awkward, particularly when used in a business setting.
In contrast, most computer pointing devices, such as mice and trackballs, are less bulky. Mice and trackballs both include a housing partially enclosing a rotatable ball and have one or more actuatable buttons. Electronic encoders sense the rotation of the ball and generate signals ("counts") that indicate the ball's rotation. The counts are used to control the magnitude and direction of two-dimensional movement of a cursor or pointer on a display screen of the computer. Such mice, however, provide only two position signals corresponding to two-dimensional movement.
U.S. Pat. Nos. 5,298,919 to Chang and 5,313,230 to Venolia et al. describe mice capable of providing three-dimensional position signals that permit the illusory positioning of the cursor in three-dimensional space on a two-dimensional video display device. The patents describe mouse-input devices having a rotatable ball and a thumbwheel for providing input signals representing three-dimensional movement.
The devices disclosed by Chang and Venolia et al. teach providing only three-dimensional position signals to a computer. As noted, standard mice and trackballs provide only two-dimensional position signals to a computer. There is a need, however, for a more robust input system for providing various input signals to a computer to control not only three-dimensional positions of an object, but other options or attributes for that object.
Several of such currently available pointing devices for providing multiple input signals to a computer have disadvantages, however, in that they are uncomfortable or difficult to use, especially for relatively long periods of time. This may manifest itself in several ways, for example, the finger or hand of a user may feel tired after operating the pointing device for any length of time. Therefore, a need exists for a pointing device for providing multiple input signals to a computer that is more comfortable and easy to use.